...
checking for directory with kernel source... /usr/src/linux
checking for directory with kernel build... /lib/modules/3.14.14-gentoo/build
checking for kernel linux/version.h ... no
The file /usr/src/linux/include/INCLUDE_VERSION_H does not exist.
Please install the package with full kernel sources for your distribution
or use --with-kernel=dir option to specify another directory with kernel
sources (default is /lib/modules/3.14.14-gentoo/source).